Although upper-extremity injuries alone are usually not life-threatening, they can produce significant immediate or long-term morbidity, especially if there is an associated nerve injury. The diagnosis of an arterial injury may be readily apparent, but the excellent upper-extremity collateral circulation may create palpable distal pulses despite a significant proximal arterial injury. Therefore, a high index of suspicion and the liberal use of arteriography are necessary to avoid missing these injuries. Compression of the brachial plexus by a hematoma can produce a serious neurologic deficit. Prompt evacuation of the hematoma may significantly reduce the deficit, another fact that supports an aggressive surgical approach in these patients. The long-term results of upper-extremity vascular injuries are usually determined by the extent of any associated nerve injuries.